1. Field of the Invention
This invention relates to an apparatus for determining the burning and/or glowing rates of a smokable article, with a sensor for the incandescent zone of said article.
2. Description of the Prior Art
The term "smokable article" includes cigars, cigarillos and especially cigarettes. The problems which are significant to these smokable articles will be discussed below in relation to cigarettes.
The tobacco consumed while smoking, that is, during puffing or during the pauses between two puffs, is significant on several accounts: on one hand, conclusions may be drawn regarding product quality and, on the other hand, the consumption represents an important parameter when determining the smoke yields and hence when developing such products.
To-date, the measurements of the amounts of tobacco consumed per unit time have been feasible only at high experimental cost and, as yet, cannot be carried out in routine tests. Use has been made of the glowing rate as a useful parameter; that is, one measures the motion of the roughly conical incandescent zone per unit time when the cigarette is left to itself, i.e., when no inhalation takes place. This is, therefore, the incandescent rate of travel during a single, long pause between two puffs.
The conventional and routine determination of this glowing of travel is obtained by measuring the total duration of glow. That is, a time interval is ascertained which is required by the incandescent zone of a glowing cigarette to cover a precisely defined path length.
Instrumentation for determining glow rate, i.e., the speed of the incandescent zone without any puffing, is known from the German Offenlegungsschrift No. 1,757,660.
Two stationary phototransistors are positioned a predetermined distance apart parallel to the burning cigarette which is held in a fastening means. The two phototransistors each emit a pulse when the incandescent zone of the cigarette passes them. From the time interval between the two pulses and the predetermined distance between the two transistors, the glowing rate or speed of the cigarette can be determined.
However, the known instrumentation allows only an integral measurement of the glowing speed. That is, an average speed is computed from the total time of glow and the predetermined path, and any interim changes in the glowing speed along this path cannot be ascertained.
However, in order to carry out quality control on various batches of cigarettes and comparisons between different products, time-changes in the glowing speed as well as the total duration of glow must be ascertained.
Further, the known instrumentation does not allow measuring the burning rate, i.e., the incandescent travel rate during the puff phases. There is increased conversion of the tobacco into smoke during the puff phases on account of ventilation, and hence the incandescent zone moves more rapidly, in superposition to the pure and slower glowing speed. This burning rate cannot be ascertained using the known, integrally measuring instrumentation.